Identifies and organizes the potential causes of a business problem. Uses an easy and understandable format. Used to identify the sources of process variation. It is also called Ishikawa Diagram and Cause and Effect Diagram.
Identifies the causes of an undesirable effect of a problem. It is also possible to identify the hierarchy of causes including the possible root causes. Brings attention to the primary factors affecting the quality of a product or service. These factors need to be optimized in order to reduce the amount of process variation. The outcome can provide initial information to later problem solving tools.
Helps to create ideas about the possible causes of a problem before it happens. An effective cause prevention tool. Helps to identify the potential factors causing an effect to prevent future problems. Can also be used in product design and to plan new processes.
Potential causes are sometimes called the process input variables. They are normally grouped into categories for easier sharing and reference. These are often called the 6 Ms.
- Fishbone Diagram How to Construct a Fishbone Diagram: Clearly define the effect of the problem. Write it down at the center right of a large piece of paper. Determine the major categories of causes. Write them on the branches of the diagram. Use brainstorming to log all possible causes under the appropriate branches. Use 5 Whys to search for root causes then add them to the diagram.
- Fishbone Diagram How to Construct a Fishbone Diagram: Take time to ensure the appropriateness of the recorded information. Update the chart as new causes become apparent. Mark or assign numbers near to the key causes to show their relative priority. Collect data and investigate to verify the key causes are actual. Plan and implement actions to address the key causes.
- Fishbone Diagram Ways of Finding More Causes: Keep asking questions to encourage everyone to participate. Involve other people, especially those who have experience in the process. Leave the chart on the wall for few days and encourage passers-by to contribute. Take a break or do something to take the team’s mind off the current thoughts.
- Fishbone Diagram Further Information: Different names may be used for the same category. • •
Procedures could be used instead of Methods. Equipment could be used instead of Machines.
You may even create your own branches that suit your needs. An affinity diagram could be used to create the branches of the diagram from the titles of the affinity sets. Don’t overload categories. •
- Fishbone Diagram Further Information: Beware of adding causes which are actually solutions. A Cause and Effect Matrix could be used to prioritize the causes of the problem. Prioritizing and selecting the key causes will minimizes the need for more statistical evaluation of inputs that are unlikely to have an impact on the output. Y1 Y2 Y3 Y4 X1
